LeetCode:Path Sum II

Path Sum II

Total Accepted: 84038 Total Submissions: 293138 Difficulty: Medium

Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum.

For example:
Given the below binary tree and sum = 22,

              5             / \            4   8           /   / \          11  13  4         /  \    / \        7    2  5   1

return

[   [5,4,11,2],   [5,8,4,5]]

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 (E) Path Sum (E) Binary Tree Paths

思路：

还是DFS。

c++ code:

/** * Definition for a binary tree node. * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    vector<vector<int>> pathSum(TreeNode* root, int sum) {                vector<vector<int>> paths;        vector<int> path;                pathSum(root, sum, path, paths);        return paths;    }        // 自定义函数  DFS    void pathSum(TreeNode* root, int sum, vector<int>& path, vector<vector<int>>& paths) {        if(!root) return;                path.push_back(root->val);                if(!(root->left) && !(root->right) && sum==root->val) paths.push_back(path);        pathSum(root->left, sum - root->val, path, paths);        pathSum(root->right, sum - root->val, path, paths);                path.pop_back();    }    };